We report the fabrication of both n-type and p-type WSe2 field effect transistors with hexagonal boron nitride passivated channels ionic-liquid (IL)-gated graphene contacts. Our transport measurements reveal intrinsic channel properties including a metal-insulator transition at characteristic conductivity close to quantum conductance e2/h, high ON/OFF ratio >107 170 K, large electron hole mobility ~200 cm2V-1s-1 160 K. Decreasing temperature 77 K increases electrons ~330 that holes ~270...

We report a new strategy for fabricating 2D/2D low-resistance ohmic contacts variety of transition metal dichalcogenides (TMDs) using van der Waals assembly substitutionally doped TMDs as drain/source and with no intentional doping channel materials. demonstrate that few-layer WSe2 field-effect transistors (FETs) exhibit low contact resistances ∼0.3 kΩ μm, high on/off ratios up to >10(9), drive currents exceeding 320 μA μm(-1). These favorable characteristics are combined two-terminal hole...

Electrical and optoelectronic properties of few-layer black phosphorus field-effect transistors are investigated through spatial-, polarization-, gate-, bias-dependent photocurrent measurements.

We report the fabrication of ionic liquid (IL) gated field-effect transistors (FETs) consisting bilayer and few-layer MoS2. Our transport measurements indicate that electron mobility about 60 cm2V-1s-1 at 250 K in devices exceeds significantly comparable back-gated devices. IL-FETs display a increase from 100 180 to 220 77 good agreement with true channel determined four-terminal measurements, ambipolar behavior high ON/OFF ratio >107 (104) for electrons (holes), near ideal sub-threshold...

Van der Waals layered materials, such as transition metal dichalcogenides (TMDs), are an exciting class of materials with weak interlayer bonding, which enables one to create so-called van heterostructures (vdWH). One promising attribute vdWH is the ability rotate layers at arbitrary azimuthal angles relative another. Recent work has shown that control twist angle between can have a dramatic effect on TMD properties, but been treated solely through use rigid-lattice moiré patterns. No atomic...

An emerging class of semiconductor heterostructures involves stacking discrete monolayers such as transition metal dichalcogenides (TMDs) to form van der Waals heterostructures. In these structures, it is possible create interlayer excitons (ILEs), spatially indirect, bound electron–hole pairs with the electron in one TMD layer and hole an adjacent layer. We are able clearly resolve two distinct emission peaks separated by 24 meV from ILE a MoSe2/WSe2 heterostructure fabricated using...

We report low-temperature scanning tunneling microscopy characterization of MoSe2 crystals and the fabrication electrical field-effect transistors on both SiO2 parylene-C substrates. find that multilayer devices show a room-temperature mobility close to bulk (100-160 cm(2) V(-1) s(-1)), which is significantly higher than substrates (≈50 s(-1)). The types are nearly thickness-independent. Our variable-temperature transport measurements reveal metal-insulator transition at characteristic...

To enhance the cost effectiveness of distribution automation system (DAS), this paper proposes immune algorithm (IA) to derive optimal placement switching devices by minimizing total customer service outage and investment line switches. The reliability index each zone defined boundary switches is derived solve expected energy not served due fault contingency, interruption then determined according type power consumption within zone. demonstrate proposed IA methodology switches, a practical...

Two-dimensional (2D) materials exhibit many exciting phenomena that make them promising as for future electronic, optoelectronic, and mechanical devices. Because of their atomic thinness, interfaces play a dominant role in determining material behavior. In order to observe exploit the unique properties these materials, it is therefore vital obtain clean repeatable interfaces. However, conventional stacking atomically thin layers typically leads trapped contaminants spatially inhomogeneous...

Transition-metal dichalcogenides (TMDs) are an exciting class of 2D materials that exhibit many promising electronic and optoelectronic properties with potential for future device applications. The TMDs expected to be strongly influenced by a variety defects which result from growth procedures and/or fabrication. Despite the importance understanding defect-related phenomena, there remains need quantitative nanometer-scale characterization over large areas in order understand relationship...

We investigate the photocurrent generation mechanisms at a vertical p-n heterojunction between black phosphorus (BP) and molybdenum disulfide (MoS2) flakes through polarization-, wavelength-, gate-dependent scanning measurements. When incident photon energy is above direct band gap of MoS2, response demonstrates competitive effect MoS2 BP in junction region. In contrast, if below but BP, exhibits same polarization dependence as that BP-metal junction, which nearly parallel to channel. This...

We present a paradigm for encoding strain into two-dimensional materials (2DMs) to create and deterministically place single-photon emitters (SPEs) in arbitrary locations with nanometer-scale precision. Our material platform consists of 2DM placed on top deformable polymer film. Upon application sufficient mechanical stress using an atomic force microscope tip, the 2DM/polymer composite deforms, resulting formation highly localized fields excellent control repeatability. show that SPEs are...

Monolayer transition metal dichalcogenides are promising materials for valleytronic operations. They exhibit two inequivalent valleys in the Brillouin zone, and valley populations can be directly controlled determined using circularly polarized optical excitation emission. The photoluminescence polarization reflects ratio of populations. A wide range values degree emission, Pcirc, has been reported monolayer WS2, although reasons disparity unclear. Here we optically populate one valley,...

Monolayers of transition-metal dichalcogenides (TMDs) are promising components for flexible optoelectronic devices because their direct band gap and atomically thin nature. The photoluminescence (PL) from these materials is often strongly suppressed by nonradiative recombination mediated midgap defect states. Here, we demonstrate up to a 200-fold increase in PL intensity monolayer MoS2 synthesized chemical vapor deposition (CVD) controlled exposure laser light the ambient. This spatially...

We report the pH response enhancement of electrolyte-gated graphene field effect transistors by controllably introducing edge defects. An average improvement from 4.2 to 24.6 mV/pH has been observed after downscaling pristine into nanoribbon arrays with electron beam lithography (EBL) and oxygen plasma. attribute improved in nanoribbons increased number hydroxyl groups attached defects as length surface area ratio increases decreasing width. Moreover, shift Dirac point change found be...

van der Waals heterostructures (vdWHs) leverage the characteristics of two-dimensional (2D) material building blocks to create a myriad structures with unique and desirable properties. Several commonly employed fabrication strategies rely on polymeric stamps assemble layers 2D materials into vertical stacks. However, properties such frequently are degraded by contaminants, typically unknown composition, trapped between constituent layers. Such therefore, impede studies intrinsic hinder their...

We report continuous-wave second harmonic and sum frequency generation from two-dimensional transition metal dichalcogenide monolayers their heterostructures with pump irradiances several orders of magnitude lower than those conventional pulsed experiments. The high nonlinear efficiency originates above-gap excitons in the band nesting regions, as revealed by wavelength-dependent order optical susceptibilities quantified four common monolayer dichalcogenides. Using excitation spectroscopy...

Quantum emitters are essential components of quantum photonic circuitry envisioned beyond the current optoelectronic state-of-the-art. Two dimensional materials attractive hosts for such emitters. However, high single photon purity required is rarely realized due to presence spectrally degenerate classical light originating from defects. Here, we show that design a van der Waals heterostructure effectively eliminates this spurious light, resulting in purities suitable variety technological...

The twist angle between the monolayers in van der Waals heterostructures provides a new degree of freedom tuning material properties. We compare optical properties WSe2 homobilayers with 2H and 3R stacking using photoluminescence, Raman spectroscopy, reflectance contrast measurements under ambient cryogenic temperatures. Clear stacking-dependent differences are evident for all temperatures, both photoluminescence spectra exhibiting blue shift spectral features compared to bilayers. Density...

The immune algorithm (IA) is proposed to derive the rephasing strategy arrangement of laterals and distribution transformers enhance three-phase balancing systems. multi-objective function formulated by considering unbalance phasing currents, customer service interruption cost (CIC) labour perform optimal strategy. For each feasible strategy, number customers affected with total load demand outage duration time are used calculate impact system reliability because engineering works. To...

Electronic applications of transition-metal dichalcogenides (TMDs) might require $p$-type or $n$-type doping. Heavy doping TMDs also facilitates the formation low-resistance ohmic contacts, which is essential for both device and fundamental study electrical transport in these materials. The authors succeed synthesizing WSe${}_{2}$ samples substituted with Nb ($p$-doped) Re ($n$-doped), systematically characterize their properties, finally combine them to demonstrate an unconventional $p-n$ diode.

We examine different cases of heterostructures consisting WS2 monolayers grown by chemical vapor deposition as the optically active material. show that degree valley polarization is considerably influenced material type used to form heterostructure. Our results suggest interaction between and graphene (WS2/Gr) has a strong effect on temperature-dependent depolarization (i.e., decrease in with increasing temperature), degrees reaching 24% at room temperature under near-resonant excitation....

Abstract Second harmonic generation (SHG) is a nonlinear optical response arising exclusively from broken inversion symmetry in the electric‐dipole limit. Recently, SHG has attracted widespread interest as versatile and noninvasive tool for characterization of crystal emerging ferroic or topological orders quantum materials. However, conventional far‐field optics unable to probe local at deep subwavelength scale. Here, near‐field imaging 2D semiconductors heterostructures with spatial...

Bilayers of 2D materials offer opportunities for creating devices with tunable electronic, optical, and mechanical properties. In van der Waals heterostructures (vdWHs) where the constituent monolayers have different lattice constants, a moiré superlattice forms length scale larger than constant either material regardless twist angle. Here, we report appearance Raman modes from nearly aligned WSe2-WS2 vdWHs in range 240-260 cm-1, which are absent both homobilayers WSe2 WS2 largely misaligned...

Introduction Acute kidney injury (AKI) is a major and unmet medical need, characterized by sudden onset of dysfunction that often occurs within 7 days. Adipose-derived stem cells (ADSCs) are known for their regenerative, differentiative, repair abilities, making them promising therapeutic option injury. Platelet-rich fibrin releasate (PRFr), derived from platelet-rich after static incubation, contains numerous growth factors may promote the differentiation proliferation cells. Additionally,...